I started the timing chain replacement a week ago. Last night I came to an impasse.
-I bought the kit from Mini
-I bought the tools from Amazon
-I got all the way to the point where I turn the motor by hand to check for proper installation, and that's where the problems started.
- I turned the motor 3/4 of a turn without any tension on the chain. the chain slipped on the VANOS sprocket. Likely 3-6 teeth.
-I stopped and turned the crank back to 90° BTDC
- I then moved the cam sprockets back and put all locks back in place in the correct positions.
- I tightened the cams back down, but had all of the slack on the front side of the motor.
- I put the tensioner in this time, put the engine back together, and attempted to start the car. (all the chain slack was on the opposite side from the tensioner and now the tensioner side was very tight)
-The car started and ran rough for about 3 seconds then stalled.
-----I took the engine apart again and loosened the cam sprockets. put new sprocket bolts in and installed the pre-tension tool to 6NM and re-tightened the cams to spec.
-put all back together and the car will now only turn over(sluggishly) but now start.

I'm at a loss here. I've inspected connections and vacuum lines. Gone over all of my procedures. racked my brain only to come to the conclusion that my one mistake could simply not be catastrophic. (bent valves, rebuild head, death and mayhem)

I'm looking for any help or ideas or helpful experiences that can help lead me to the promise land.

 

Take a deeeep breath and let's do it step by step. I guess the first thing you ought to do is check the timing again using the tools. visual inspection is NOT an option.

If the timing is spot on, then you need to read the codes even if there is no check engine light.

let us know

also, where are you located?

 

I'm in Cincinnati Ohio. I am going to get back to it on Sunday. This is a standard shift, and I only find one hole in the flywheel to put the locking pin in. I will re-lock the timing in position using the tools and inspect.

How far far out would it take for the pistons and valves to make contact, and could I even bend a valve turning by hand?( and not notice!)

 

OH, 9 hrs away...I liked it when I visited a friend couple of years ago...

when you turn it by hand and let's say it is out of time, you will feel the piston hitting the valves and it wont turn.

the starter is much more powerful than a hand turn and it "yanks" on the chain.

also, check the ground strip on the side of the bracket.

 

Correct sequence of events to set timing --- summarized and brief:
Anytime the cams are not synchronized with the flywheel, they should be loosened so they don't lift the valves as the flywheel is turned. So 1st thing is to lock the flywheel in place.
2. Loosen cam sprockets --- crank sprocket may stay tightened
3. Lock cams --- cams and chain guides already installed to spec
4. Install and adjust pre-tensioner
5. Tighten cam sprockets
6. Remove pre-tensioner and finish assembly

Your above procedure implies the sprockets were tightened without using the pre-tensioner first --- big mistake! Doing this level of maintenance, a novice to Mini's should at least have a copy of the Bentley manual --- for torque settings and tightening sequence, if nothing else.

And FYI --- with chain installed, hand rotation is to be CW only. Apparently the Vanos doesn't like CCW rotation.

 

Oldbrokenwind,

I referred to the "cams" when I should have said "cam sprockets".

Spelling error with with the word "now"
The car will NOT start. It WILL turn over.

When you you say the VANOS does not to be turned counterclockwise, what exactly would be the side effect?

 

MiniToBe,
I checked the ground strap and it was on and tight. (the one on the motor mount and the one on the valve cover)
I did not feel any interference when turning the motor by hand. I am positive that the only time any of the timing components were out of "time" Is when the chain slipped during my 3/4 of a turn of the crank on the very first "hand turn". I do not believe that the timing is off at all, or that I bent a valve. I keep thinking I'm missing something here, but I cannot find what it is.

If the VANOS does not like to be turned counterclockwise, what are the repercussions? I can turn this motor all day long(after setting the crankshaft and cam shafts with the tool) and the timing seems to be perfect. valves opening and closing on the proper strokes. If the VANOS only adjusts at certain rpm, then shouldn't the car start, but maybe run rough at those rpm's?

 

I know absolutely nothing about the operation of the Vanos, I'm just quoting from the Bentley manual and mentioning what others have said in their re-build / repair threads.

OK, regardless of the grammar and spelling, at least you now have the info you need to do the chain replacement properly. I'm guessing your main problem was tightening the sprockets while the chain was still loose someplace. Another guess --- low battery is causing "sluggish" cranking.

FYI --- I just completed a complete re-build on my '07MCS. I used the above summarized and brief procedure, plus excessive engine assembly lube on cams, lifters, followers, etc. Battery is about 2 yrs old and sat in a corner for 6 - 7 months collecting dust during the re-build --- no charger was used. Did a compression test (to check my work and start oil circulation) before plug and coil install, then started it --- no problem with timing or cranking.

 

Kudos on your 07'.
I'm not here to be bashed for mistakes. I'm here for insight from someone who might have had a similar issue, or might have useful information on what I might be missing, so that I may one day drive my car again.

 

My intent was not to bash you for your mistakes. But unfortunately, I don't know of any better way to let you know how the process you followed is different from the recommended process. You are not the first person to get bad results from a DIY timing chain replacement. This is a complex process for an "unusual" product design. Then when it's compounded by "sluggish" cranking, the process gets worse. And getting help from unknown online sources???

Thank you for the kudos --- I only mentioned it to let you know that I've done the chain change before --- twice actually, with no problems either time. I've had my share of "do-overs", just not with the timing chain.

Obviously, you're free to either accept or reject our recommendations. Either way, I wish you the best of luck.

 

Worse case go through the process again. Tip, I used four dowels inserted through the spark plug holes to get an idea when the piston heads were level. Even if it got totally messed up as long as nothing is bent you should be able to get it back correct. Pin the fly wheel and get the cams in the right position. Text on cams should be at top.

 

I used #12 solid wire that worked perfect for that purpose.

 

So the car is running in top condition now.

What I was missing: I was going to change the oil before the first attempt to start the car. I broke the oil filler cap while removing the old filter. I had to order a new cap from BMW, so in the interim, I put the old cap on with no filter. That's it. That's the key. I believe the filter MUST be in place for the car to run.

If that was not the issue, then it was simply a miracle.

Other than two weeks of utter frustration, the timing chain replacement can now be considered a success.

 

Congrats!

 

WOW...who know. a filter or the lack of will kill the car!!!

 

Without filter being in place oil couldn't build enough of pressure to get to the head. You are lucky I would say the engine didn't get stalled.

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